circular-list

I have data that is arranged in a ring structure (or circular buffer ), that is it can be expressed as sequences that cycle: ...-1-2-3-4-5-1-2-3-.... See this picture to get an idea of a 5-part ring: I'd like to create a window query that can combine the lag and lead items into a three point array, but I can't figure it out. For example at part 1 of a 5-part ring, the lag/lead sequence is 5-1-2, or at part 4 is 3-4-5. Here is an example table of two rings with different numbers of parts (always more than three per ring): create table rp (ring int, part int); insert into rp(ring, part) values(1

I want to use a circular list. Short of implementing my own ( like this person did ) what are my options? Specifically what I want to do is iterate over a list of objects. When my iterator reaches the end of the list, it should automatically return to the beginning. (Yes, I realize this could be dangerous.) See Vladimir's definition of a circular_iterator : "A circular_iterator will never be equal with CircularList::end(), thus you can always dereference this iterator." There's no standard circular list. However, there is a circular buffer in Boost, which might be helpful. If you don't need